Keys With Double-Diving-Board Spring Mechanisms

ABSTRACT

Keys may be formed for keyboards. The keyboards may be attached to electronic devices such as computers or may be formed within a portable computer or other electronic equipment. A keyboard may be provided with a planar housing member such as a top plate. The top plate may have openings through which key caps protrude. Each key cap may be attached to a respective spring mechanism. The spring mechanism for each key may have first and second diving-board structures that flex about respective parallel flex axes. A dome switch may be mounted under each spring mechanism. The dome switch is compressed when the key cap is pressed and the first diving-board structure moves towards the dome switch. The top plate may have edge portions surrounding each key opening that form upstop structures that prevent the key caps and spring mechanisms from tilting when the dome switch is compressed.

This application is a continuation of patent application Ser. No.12/724,143, filed Mar. 15, 2010, which is hereby incorporated byreference herein in its entirety.

BACKGROUND

This relates to electronic devices and, more particularly, to keys forelectronic devices such as keyboards and equipment that includeskeyboards.

Electronic devices such as computer keyboards and portable computershave keys. Keys generally include a plastic key cap attached to a switchmechanism. The key caps may be labeled with alphanumeric characters.When a key is pressed, the switch mechanism closes. The closed state ofthe switch mechanism may be detected by circuitry in the keyboard.

Keys are sometimes provided with springs. For example, some keyboardsuse a bucking spring design in which a coil spring biases each key cap.Scissor-type springs may also be used in keyboards to help provide keycaps with spring action. Keyboards such as these tend to exhibit largeamounts of travel. This may not be desirable, particularly in keyboardapplications that require low profile designs and quiet operation.

In keyboards with relatively low amounts of key travel, key caps aresometimes attached directly to dome switches. Keyboards of this type maysometimes exhibit rattle due to insufficient control of the lateraldisplacement of the keycaps or may provide undesirably low amounts oftactile feedback due to the modest amount of spring action provided bythe dome switches.

It would therefore be desirable to be able to provide improved keys andkeyboards for use in electronic equipment such as computers and computeraccessories.

SUMMARY

Keys may be provided for keyboards. The keyboards may be connected toexternal equipment or may be formed as an integral portion of a portablecomputer or other device.

Each keyboard may have a housing. The housing may have a planar uppersurface such as a metal top plate that has key openings. Keys in thekeyboard may be provided with key caps. Each key cap may be providedwith a label. The key caps may protrude through the key openings in themetal top plate.

A double-diving-board spring mechanism may be mounted under each keycap. A dome switch may be mounted below each spring mechanism. When auser pressed downwards on a key cap, the double-diving-board springmechanism pressed downwards on a corresponding dome switch.

Each spring mechanism may have first and second diving-board structuresthat flex about respective parallel flex axes. The top plate may haveedge portions surrounding each key opening that form upstop structures.The upstop structures for each key may prevent the key cap and springmechanism for that key from tilting when the dome switch for that key iscompressed.

Further features of the invention, its nature and various advantageswill be more apparent from the accompanying drawings and the followingdetailed description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an illustrative portable computer thatmay be provided with a keyboard and keys in accordance with anembodiment of the present invention.

FIG. 2 is a perspective view of an illustrative keyboard that may beprovided with keys in accordance with an embodiment of the presentinvention.

FIG. 3 is an exploded perspective view of a key for a keyboard inaccordance with an embodiment of the present invention.

FIG. 4 is a cross-sectional side view of a key in a keyboard inaccordance with an embodiment of the present invention.

FIG. 5 is a bottom view of an illustrative key in a keyboard inaccordance with an embodiment of the present invention.

FIG. 6 is a perspective view of an illustrative key in a keyboard inaccordance with an embodiment of the present invention.

DETAILED DESCRIPTION

This relates to keys for electronic equipment. The equipment in whichthe keys are provided may be a keypad, a stand-alone keyboard such as astand-alone computer keyboard, a keyboard that is built into anelectronic device such as a portable computer, or other suitableelectronic devices.

An illustrative computer that may be provided with a keyboard is shownin FIG. 1. As shown in FIG. 1, portable computer 10 may have a housing12. Housing 12, which is sometimes referred to as a case, may be formedfrom one or more individual structures. For example, housing 12 may havea main structural support member that is formed from a solid block ofmachined aluminum or other suitable metal. One or more additionalstructures may be connected to the housing 12. These structures mayinclude, for example, internal frame members, external coverings such assheets of metal, etc. Housing 12 and its associated components may, ingeneral, be formed from any suitable materials such as plastic,ceramics, metal, glass, composites, etc.

Case 12 may have an upper portion 26 and a lower portion 28. Lowerportion 28 may be referred to as the base or main unit of computer 10and may contain components such as a hard disk drive, battery, and mainlogic board. Upper portion 26, which is sometimes referred to as a coveror lid, may rotate relative to lower portion 28 about rotational axis16. Portion 18 of computer 10 may contain a hinge and associated clutchstructures and is sometimes referred to as a clutch barrel.

Lower housing portion 28 may have a slot such as slot 22 through whichoptical disks may be loaded into an optical disk drive. Lower housingportion may also have a touchpad such as touchpad 24 and may have keys40. Keys 40 may protrude from planar housing surface 42. Keys 40 mayinclude letter keys, number keys, keys labeled with symbols, or othersuitable keys. Keys 40 may be individual keys or as part of a keyboardsuch as keyboard 20 (e.g., a QWERTY keyboard). If desired, keys 40 maybe formed as part of a keypad (e.g., keyboard that contains primarily orexclusively number keys and mathematical function keys).

Additional components may be mounted to upper and lower housing portions26 and 28. For example, upper and lower housing portions 26 and 28 mayhave ports to which cables can be connected (e.g., universal serial busports, an Ethernet port, a Firewire port, audio jacks, card slots,etc.). Buttons and other controls may also be mounted to housing 12.

Openings may be formed in the surface of upper and lower housingportions to allow sound to pass through the walls of housing 12. Forexample, openings may be formed for microphone and speaker ports. Withone illustrative arrangement, speaker openings such as speaker openings30 may be formed in lower housing portion 28 by creating an array ofsmall openings in the surface of housing 12.

A display such as display 14 may be mounted within upper housing portion26. Display 14 may be, for example, a liquid crystal display (LCD),organic light emitting diode (OLED) display, or plasma display (asexamples). A glass panel may be mounted in front of display 14. Theglass panel may help add structural integrity to computer 10. Forexample, the glass panel may make upper housing portion 26 more rigidand may protect display 14 from damage due to contact with keys or otherstructures.

An illustrative stand-alone keyboard that may contain keys 40 is shownin FIG. 2. As shown in FIG. 2, keyboard 32 may have a housing such ashousing 38. A cable 36 and connector 34 may be connected to housing 38.If desired, keyboard 32 may include batteries and wirelesscommunications circuitry.

Housing 38 may be formed from metal, plastic, carbon-fiber compositesand other composites, glass, ceramics, other materials, and combinationsof these materials. Housing 38 may be formed from one or more structuralpieces such as planar upper surface member 42. As with planar surfacemember 42 of computer 10 in FIG. 1, keys 40 may protrude throughopenings in planar surface 42. Planar housing surfaces such as surface42 of FIG. 2 and surface 42 of FIG. 1 are sometimes referred to as topplates, top plate structures, and plate members. The openings that areformed in planar housing structures such as top plates 42 of FIGS. 1 and2 may be square, rectangular, circular, oval, etc. In a typicalarrangement, the openings in top plates 42 are square and rectangularand accommodate corresponding square and rectangular keys 40.

FIG. 3 shows an exploded perspective view of an illustrative key. Asshown in FIG. 3, key 40 may include key cap 44 (sometimes referred to asa key member or button structure). A label such as an alphanumericcharacter or symbol may be formed on the upper surface of key cap. Label60 may, for example, be formed by printing ink or paint on the surfaceof key cap 44, by machining or molding a desired shape into key cap 44,by etching a desired pattern into key cap 44, by laser etching a desiredpattern into key cap 44, by laser etching a desired pattern into key capbefore or after printing ink or paint on the surface of key cap 44, byattaching a sticker to the surface of key cap 44, etc. Key cap 44 may beformed from plastic, metal, glass, ceramic, composites, other materials,or combinations of these materials. For example, key cap 44 may beformed from a plastic button-shaped member.

Top plate 42 may be provided with an opening such as opening 62. Opening62 preferably has inner dimensions that are sufficiently large toaccommodate the outer periphery of key cap 44. With one suitablearrangement, there may be about a 0.1 mm to 0.3 mm clearance betweeneach of the outer edges of key cap 44 and each of the correspondingedges of opening 62. The edges of opening 62 may be have verticalsidewalls or may have a notched shape. When provided with a notchedshape, portions of key cap 44 may, if desired, overlap the edges (e.g.,by covering the lower horizontal surfaces of the notches).

Top plate 42 may be formed from plastic, metal, glass, ceramic,composites, other materials, or combinations of these materials. Forexample, top plate 42 may be formed from a layer of metal such asaluminum. The aluminum or other metal that makes up top plate 42 may beanodized or provided with other coatings. The thickness of top plate 42may be between 0.3 and 0.5 mm, between 0.2 and 0.6 mm, between 0.05 and1 mm, between 0.05 and 3 mm, or may be any other suitable thickness. Thetop plate may, for example, form part of a unitary housing for computerhousing 12 of FIG. 1 or may form part of a unitary housing for housing38 of FIG. 2. The top plate may also be formed as a separate structurethat is attached to other housing structures (e.g., to form a cover orother planar top surface for a keyboard).

Key 40 may include a spring mechanism such as spring mechanism 64. Keycap 44 may be attached to spring mechanism 64 using adhesive 78 or othersuitable attachment mechanisms (e.g., screws or other fasteners,springs, clips, mating engagement features, etc.). Because springmechanism holds key cap 44 securely within the opening 62, the outeredges of key cap 44 will generally not strike the inner edges of opening62. This prevents the keys from rattling.

When key cap 44 is pressed downwards in direction 75 by the finger of auser or other object, central portion 70 of spring mechanism 64 maypress downwards in direction 75 against dome switch 66 (e.g., on top ofnub 68 of switch 66). Dome switch 66 may be formed from a flexible domemember such as an elastomeric or metal dome member. The underside of thedome member may be coated with metal, so that depression of the domeswitch causes the metal to short two corresponding traces (e.g., traceson a printed circuit board to which dome switch 66 is mounted). Nubmember 68 may be formed from epoxy or other suitable materials andserves as an actuation point against which spring mechanism 64 may bearwhen depressed.

Spring mechanism 64 may be formed from a sheet of metal, plastic, orother suitable material such a planar sheet member 80. With one suitablearrangement, sheet member 80 is formed from a layer of stainless steelthat is about 0.2 mm thick, between 0.1 mm and 0.3 mm thick, between0.05 mm and 0.3 mm thick, or between 0.05 mm and 0.7 mm thick (asexamples). Thinner spring mechanism sheets tend to make spring mechanism64 more flexible. Thicker sheets tend to make spring mechanism 64stiffer.

Spring mechanism 64 has a double-diving-board design. Outer U-shapedgroove 48 surrounds first substantially rectangular diving boardstructure 74. Inner U-shaped groove 50, which faces in the oppositedirection from outer U-shaped groove 48, is nested within outer U-shapedgroove 50 and surrounds second substantially rectangular diving boardstructure 70.

U-shaped groove 48 includes side grooves 48A and 48B that are connectedby tip groove 48C. U-shaped groove 50 includes side grooves 50A and 50Bthat are connected by tip groove 50C. Adhesive 78 may be formed ondiving-board structure 70.

The double diving board layout of spring mechanism 64 forms a springthat provides key cap 44 with a restoring upwards force when key cap 44is depressed. When pressed, key cap 44 moves downwards in direction 75and the diving-board shapes in switch mechanism 64 flex about axis 52and 56. In particular, hinge portions 84 allow tip portion 72 of member70 to flex downwards in direction 75, so that inner diving boardstructure 70 pivots in the opposite direction (i.e., direction 58)around flex axis 56. At the same time, hinge portions 82 of switchmechanism 64 allow tip portion 76 of outer diving board structure 74 toflex downwards in direction 75, so that outer diving board structure 74pivots in direction 54 about flex axis 52. When key cap 44 movessufficiently in direction 75, the dome membrane in dome switch 66 iscompressed and the dome switch closes to indicate that key 40 has beenactuated.

Because the diving board structures of switch mechanism 64 are orientedso that their tips point in opposite directions, key cap 44 does nottilt excessively when depressed near the center of key cap 44. Tip 76 ofdiving board structure 74 is aligned with flex axis 56 of diving boardstructure 70, whereas tip 72 of diving board structure 70 is alignedwith flex axis 52 of diving board structure 74. As a result, thepotential tilt that is induced when one diving board structure bendsabout its flex axis offsets the potential tilt when the other divingboard structure bends about its flex axis. Because the tilts from thediving boards offset one another, key cap 44 exhibits little or no tiltas key 40 is actuated (e.g., as a user presses down on key cap 44 nearthe center of key cap 44). When a user presses down on key cap 44 nearan edge of key cap 44, key cap 44 may exhibit limited tilt in thedirection the user presses.

A cross-sectional side view of an illustrative key cap resulting fromtaking a cross-section through key 40 of FIG. 3 along a cross-sectionalline that is parallel to axis 56 and axis 54 is shown in FIG. 4. Asshown in FIG. 4, key cap 44 rests on inner diving board member 70. Inthe example of FIG. 4, key cap 44 has portions 116 that bear againstdiving board member 70. Portions 116 may restrain the movement of keycap 44 along the horizontal axis of FIG. 4 and along the axis into andout of the plane of FIG. 4.

Key cap 44 may have an optional hollow inner cavity (cavity 88). Whenkey cap 44 includes optional cavity 88, adhesive 78 may be located underperipheral portions of key cap 44.

In the example of FIG. 4, sheet member 80 is mounted to top plate 42.Screws 118 may be screwed into bores 120 in top plate 42 or othersuitable attachment mechanisms such as adhesive may be used in securingsheet member 80 and spring mechanism 64 (e.g., diving board members 70and 74) relative to top plate 42. In general, any desired number ofscrews 118 (or other attachment mechanisms) may be used in securingsheet 40 to top plate 42. Screws 118 and other attachment mechanismsused in securing sheet 40 to top plate 42 may be located in any desiredlocations.

Dome switch 66 may be mounted to printed circuit board 90. Printedcircuit board 90 may be formed from a rigid printed circuit boardsubstrate such as fiberglass-filled epoxy, a flexible printed circuitboard substrate such as a layer of polymer (e.g., polyimide), or anyother suitable substrate (e.g., plastic). Conductive traces on printedcircuit board 90 may form terminals for dome switch 66. When dome switch66 is compressed, these terminals may short to one another, therebyclosing switch 66. Connectors such as connectors 98 and 102 and flexcircuit cable 100 (or other suitable interconnect structures) may beused to connect printed circuit board 90 to main logic board 104. Mainlogic board 104 may include integrated circuits for processing keyswitch signals from keys 40. In the example of FIG. 4, main logic board104 is mounted to keyboard housing structure 106 (e.g., a lower planarmember that is part of housing 38 of FIG. 2 or that is part of housing12 of computer 10 of FIG. 1). Screw 94 may be screwed into threaded bore96 in housing boss 92 or other suitable attachment mechanisms may beused in securing boards 90 and 104 relative to top plate 42.

When key cap 44 is pressed downwards, the center of key cap 44 bearsagainst central nub 68 on dome switch 66. In this type of situation, nub68 may tend to serve as a central pivot point for key cap 44. If, forexample, a user presses key cap 44 downwards at one of its four cornersor at another off-center location, the portion of key cap 44 that islocated on the opposing side of nub 68 will tend to be pivoted upwards.If not properly controlled, this tendency for key cap 44 to pivot maycause key cap 44 to tilt by an undesirable amount during use.

Top plate 42 and spring mechanism 64 (e.g., diving board member 74) mayoverlap to prevent tilting of key cap 44. In particular, top plate 42may have upstop portions 108 that prevent key 40 from tiltingundesirably when key 40 and diving board member 70 presses downwards onnub 68 of dome switch 66. If desired, upstop portions 108 may be formedfrom protrusions on plate 42. When upstop portions 108 are formed fromprotrusions, the upstop portions may be formed as integral portions oftop plate 42 or may be formed from a layer of material that is mountedto the lower surface of top plate 42 (as examples).

During key actuation events, upstop portions 108 (e.g., the lowersurfaces of portions 108) engage the corresponding portions of sheet 80of spring mechanism 64 (e.g., the upper surfaces of portions of divingboard structures 70 and 74) to prevent one edge of key cap 44 frommoving upwards as an opposing edge of key cap 44 pivots downwards duringkey depression.

FIG. 5 shows a bottom view of key 40 and FIG. 6 shows a perspectivebottom view of key 40. FIGS. 5 and 6 illustrate how upstop portions 108may overlap tip portion 72 of inner diving board structure 70 and theedges and tip portion 76 of outer diving board structure 74. Dashed line114 (FIG. 5) shows where the cross-section of FIG. 4 was taken. Dashedline 111 (FIG. 5) follows the inner perimeter of upstop portions 108 oftop plate 42 (i.e., the innermost edges of opening 62 of FIG. 3). Asshown in FIGS. 5 and 6, additional groove structures such as grooveopening 110 may be formed in sheet 80 to help provide the diving-boardhinges formed from sheet 80 with a desired amount of flexibility.

Diving board structure 70 and key cap 44 may, if desired, be providedwith mating features that help align key cap 44 on spring mechanism 64.For example, diving board structure 70 or other portions of sheet 80 inspring mechanism 64 may be provided with protrusions 112 that mate withcorresponding recesses in the bottom of key cap 44.

The foregoing is merely illustrative of the principles of this inventionand various modifications can be made by those skilled in the artwithout departing from the scope and spirit of the invention. Theforegoing embodiments may be implemented individually or in anycombination.

1. A key comprising: a double-diving-board spring mechanism formed froma sheet of material; and a key cap mounted on the double-diving-boardspring mechanism.